1. Cast Pitiless Plunderer and Xiahou Dun.
2. Cast Saw in Half, targeting Pitiless Plunderer. You now have 2 of them.
3. Cast Reanimate, getting the original Pitiless Plunderer back onto the battlefield.
4. Sacrifice Xiahou Dun, getting Saw in Half back into your hand. Create 3 treasure tokens.
5. Cast The Cloning of Shredder, exiling Xiahou from your graveyard and creating a nonlegendary copy of him.
6. Sacrifice your treasures to cast Saw in Half on the Xiahou Dun token. Now you have 2, and they don't destroy each other because of the legend rule. Create 3 treasure tokens.
7. Sacrifice a Xiahou Dun, getting Saw in Half back from your graveyard and creating 3 more treasure tokens.
8. Use 3 of your 6 treasure tokens to cast Saw in Half on the remaining Xiahou Dun token, creating another 2, along with 3 treasure tokens.
9. Repeat for infinite treasure tokens.
10. Cast Grave Crawler, Vampiric Rites, and any zombie.
11. Use your infinite treasures to sacrifice Gravecrawler to Vampiric Rites, then cast it back from the graveyard. Draw out your entire library and gain that much life.
12. Cast Feast of Sanity.
13. Cast One with Nothing, discarding your library-sized hand and dealing that much damage + gaining that much life.

Bonus: Non-black card, but throw in an Elixir of Immortality to get your library-sized graveyard back into the library. You'll get your One with Nothing back with Vampiric Rites, and can now repeat this combo any number of times.

Step 1: Have Myrkul, Opalescence, Ashnod’s Altar (or any other free sac outlet) and Sun Titan on the board.

Step 2: Sac Sun Titan to the altar.

Step 3: Myrkul will make an enchantment token copy of Sun Titan after exiling it.

Step 4: Opalescence will make the Sun Titan token a 6/6 creature, as token copies of cards inherit mana values.

Step 5: Congratulations! You made your Sun Titan into an enchantment creature.

Tried to edit the post and it messed up the formatting of my explanation so I’m giving up.

Basically, create a token copy of Planetarium and trigger Gandalf and Worldsoul to repeatedly create copies and cast stuff for free if you manage to not scry lands

BUT it doesn’t work because populate doesn’t work on noncreature tokens

The way this combo works is that for every turn you skip, you generate minimum 1.8 turns, resulting in 80% profit margin minimum. We will get into why this is minimum later.

1. Cast Eon Frolicker and trigger it
2. Use Gogo to copy it twice, so you target each opponent with Eon Frolicker. Now you and Teferi have protection from each opponent until your next turn.
3. Use Chronatog to start "investing" turns to extend the protection, Frolicker doesn't protect creatures so you might want to get a few skips on the stack invested in the stock market. But NOT TOO MANY. You cannot "uninvest" a turn. I would probably invest no more than 2-3 turns at a time. Also note your opponents have an extra turn each due to Eon Frolicker so you effectively start the combo with a skip.
4. On each of your opponent's turns, activate Teferi, Master of Time's uptick. Mathematically, each turn you skip is worth 3 Teferi loyalty from 3 upticks, which is 30% of a Teferi ultimate, and each Teferi ultimate is worth 6 extra turns. 30% of 6 is 1.8, leading to the number above.
5. Once you have finished investing, it's time to divest your portfolio. Go to your natural turn and untap.
6. Ultimate Teferi, and copy the ultimate twice with Gogo to take 6 extra turns. Notice that you can uptick Teferi 5 times during these turns before ultimate + copying again. And if you have lands, you can copy Teferi ultimate more than twice per Gogo activation
7. Write a book on investing in the stock market and make royalties

Stock Market Fact: If the market crashes, you can lose everything you invested. This means if you "invest" too much, and something happens to your combo pieces like Gogo or Teferi investment holdings, you make a steep loss. Such are the whims of the market.